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Wheel & Gear Size



Tire and Rim Sizes
Chart shows most tires and rims,
from large to small, fat to narrow.

Gear Measures & Sizes
Gear Inch chart for 700c and 27-inch tubular wheels

Update Thursday, 30 May 2013
© 2013 bikecult.com

Tire and Rim Sizes

Countless kinds of tires and rims have been made for bicycles. Before tire and rim standards were set by the European Tire and Rim Technical Organization (ETRTO) and adopted c.1970 by the International Standards Organization (ISO), manufacturers in different countries produced their own tire and rim sizes.

Most tire and rim sizes are nominal, not always the true measure, just close designations. Bead Seat Circumference (BSC), or Bead Seat Diameter (BSD), where the tire bead seats in the rim, is the most accurate measure. French Metric tires are measured by diameter in millimeters, and by width in letters (A is narrow 20mm, D is wide 50mm). An exception came with narrow 700-size clincher tires designated as C. Fractional Inches tire sizes usually fit wheels with European straight-bead rims and British wired-on rims. Decimal Inches tire sizes usually fit America hook-bead rims. Narrow width tires (18cm to 25cm or 1-1/4" to 7/8") usually fit hook-bead rims.

Yellow rows indicate rim, tire and tube sizes usually in stock at Bike Works NYC.

Large Tire Sizes 36-inch to 26-inch:Rim Sizes:Usage:
ISO-ETRTO metricFrench metricDecimal inchesFractional inchesBead Seat Circumf.Country Orig.
Rim specs
Cycle Types
52-787
48-787
- 36x2.25 36x2-3/8
36x2-1/4
- - cruiser
unicycle
32-647 700 - 28x1-1/4 2032 Britain EA2
Holland
roadster
44-642
37-642
700A - 28x1-3/4
28x1-3/8
2016 Britain F5, EA4, E4 roadster
40-635
28-635
700B - 28x1-5/8
28x1-1/2
1994 Britain F10, F25.0, EA4 rod-brake roadster
32-631 - - 27x1-1/4 1982 Sweden road
32-630
28-630
20-630
- - 27x1-3/8
27x1-1/4
27x1
1978 Britain K2, K25.0, EA25.0 touring, road
44-623 - - 28x1-5/8 1958 Sweden roadster
70-622
60-622
52-622
49-622
44-622
700C 29x3.0
29x2.3
29x2.1
- 1955 - mountain 29er
hybrid
42-622
38-622
35-622
32-622
30-622
700C - 28x1-3/4 1955 - mountain
hybrid
Soviet roadster
tandem
28-622
25-622
23-622
20-622
18-622
700C - 28x1-3/8
28x1
1955 - touring
road
time trial
track
40-609 650-32 - 27x1-1/2 1913 Germany roadster
40-607 - - 26x1-1/2 1906 America roadster
35-599
32-599
- 26x1.375
26x1.25
- 1880 America vintage lightweight
37-597
32-597
650 - 26x1-1/4x1-3/8
26x1-1/4
1876 America
Schwinn S-5, S-6
roadster, touring
Schwinn lightweight
40-590
37-590
650A - 26x1-1/2
26x1-3/8
1854 Britain F.4, E.3, EA.3, E23.0, EA23.0, R23.0 roadster, road
40-583 700D 26x1.50 - 1845 - touring
rare GT mtb
47-585
40-585
- - 26x1-3/4
26x1-1/2
1837 Sweden roadster
60-584
52-584
650B 27.5x2.4
27.5x2.2
- 1835 - mountain
47-584
40-584
32-584
650B - 26x1-5/8
26x1-1/2
26x1-3/8
1835 France
Schwinn S-4
Britain F9
randonneur, touring, tandem
rare Raleigh, Schwinn mtb
47-571 650C - 26x1-5/8
26x1-3/4
1794 America
Schwinn S-7
Britain F9
cruiser, Schwinn middleweight
23-571
20-571
650C - 26x1
26x3/4
1794 - time trial, triathlon, small road
62-561 - - 25x1-3/8 1764 Sweden roadster
110-559
85-559
- 26x4.8
26x3.7
- 1755 - all-terrain
57-559
54-559
50-559
47-559
40-559
38-559
32-559
28-559
25-599
650x45 26x2.25
26x2.125
26x2.0
26x1.90
26x1.75
26x1.60
26x1.50
26x1.40
26x1.25
26x1
- 1755 - balloon cruiser, mountain

middleweight cruiser, atb

touring, tandem

road

Small Tire Sizes 25-inch to 7-inch:Rim Sizes:Bike Types:
ISO-ETRTO metricFrench metricDecimal inchesFractional inchesBead Seat Circumf.Country Orig.
Rim specs:
37-547
32-547
- - 24x1-3/8
24x1-1/4
1715 Schwinn
S-5, S-6
Britain K.1, E1, EA1
juvenile lightweight, Schwinn
37-541
32-541
600A - 24x1-3/8
24x1
1700 Britain E.5
Holland
juvenile, small road, wheelchair
40-540
32-540
600x35A - 24x1-3/8
24x1-1/2
1695 Britain E.5, F.3, EA21.0, F21.0, R21.0 juvenile roadster, small road, Raleigh
40-534
38-534
600B - 24x1-1/2 1676 Britain F8
Holland
France
transport
37-533 - - 26x1-1/2 - Russia small road, folding
40-531 - - 24x1-1/2 1667 Sweden small roadster
47-521 - - 24x1-3/4 1635 America
Schwinn S-7
Britain
small cruiser
47-520 - - 24x1-3/4 1633 America juvenile roadster
20-520
25-520
- - 24x1-1/8
24x1
1633 - time trial, triathlon, small road, Terry front
32-508 550x32 - 22x1-1/4 1595 Dutch juvenile roadster
57-507
50-507
47-507
40-507
600x45 24x2.125
24x1.90
24x1.75
24x1.50
24x2x1-3/4 1592 Schwinn S-2 juvenile mtb, cruiser
50-503 - - 24x2 1579 Sweden transport
37-501
32-501
- - 22x1-3/8
22x1-1/4
1575 Britain F.2, E.6, EA19.5
Italy 550x32A
juvenile roadster
37-498 - - 22x1-3/8x1-1/4 1563 Germany folding
37-490 550A - 22x1-3/8A 1539 France juvenile road, folding
37-489 - - 22x1-3/8 1535 Italy 550A
Holland 550A
small-wheel roadster
44-484 550B - 22x1-5/8x1-1/2 1520 France transport
40-482 - - 22x1-1/2 1515 Holland 550B small-wheel roadster
47-470 550C - 22x1-3/4 1475 France juvenile roadster
57-457
44-457
- 22x2.125
22x1.75
- 1435 America juvenile
37-451
32-451
28-451
- - 20x1-3/8
20x1-1/4
20x1-1/8
1416 Schwinn S-5, S-6
Italy 500x35A
Britain E.5J, EA18.0, R18.0, EB18.0
juvenile lightweight, bmx racing, recumbent
32-445 - - 20x1-1/4 - - juvenile
- - 20x1.375
20x1.25
- - America juvenile middleweight
37-440 500A - 20x1-3/8x1-1/4 1382 France juvenile, folding
37-438 - - 20x1-1/2
20x1-3/8
1375 Italy
Holland 500x35A
-
40-432 - - 20x1-1/2 1356 Holland 500x38B -
54-428
40-428
-
428x40
- 20x2
20x1-5/8x1-1/2
1345 Sweden
France
small-wheel roadster
47-419 - - 20x1-3/4 1314 Schwinn S-7 juvenile, Schwinn
57-406
52-406
47-406
44-406
500x50 20x2.125
20x1.95
20x1.75
20x1.50
20x1-3/4 1274 France
Holland
America
bmx, juvenile, folding, Moulton APB, recumbent, trailer
54-400
40-400
- - 20x2
18x1-3/8
Italy 18x1-1/4
1257 Britain E.4J, F.4J
Italy 450x32A
small-wheel roadster, folding
40-390
37-390
450A - 18x1-3/8
18x1-1/4
1225 France juvenile
32-369 - - 17x1-1/4
16x1-1/4
1169 Britain Moulton AM, recumbent
54-355
47-355
44-355
450x45 18x2.125
18x1.75
18x1.50
- 1115 Germany
America
France
folding
juvenile
35-349 - - 16x1-3/8
16x1-1/4
1097 Britain E.3J, EA14.0, EB14.0
Italy 400x32A
juvenile, folding, early Moulton
37-340
32-340
400A - 16x1-1/2
16x1-3/8
1069 France juvenile
37-337 - - 16x1-3/8A 1058 - folding Birdy
37-335 - - 16x1-3/8 738 Poland juvenile
44-317 - - 16x1-3/4 996 Schwinn S-7 juvenile, Schwinn
54-305
44-305
- 16x2.125
16x1.75
- 957 America juvenile, small bmx, folder, recumbent, trailer
37-298
32-298
- - 14x1-3/8
14x1-1/4
937 Britain E2J, F2J, EA11.7
Italy 350x32A
folding, juvenile
37-288 350A - - - French 350A folding, juvenile
62-203
57-203
- - 12-1/2x2
12-1/2x1.75
638 Italy
France
juvenile, scooters
44-194
32-194
- - 10x1-5/8
10x1-1/4
609 -
Italy
juvenile
54-152 - - 10x2 - America wheelchair
32-137 - - 8x1-1/4 - America wheelchair
54-110 - - 8x1-3/4
8x1-1/2
346 - -
47-94 200x47 - 7x1-3/4 292 Germany juvenile



Gear Measures

Bicycle evolution brought the basic definitions of gear size, including gear ratios, gear inches, meters development and gain ratio. Gear measures are meant to be simple, practical calculations, a way to communicate gear size among different bikes, relative to cadence, speed, gradient and terrain in cycling. Yet differences and inaccuracies arise between inch and metric users, and the fact that many wheel sizes are nominal and not actual accurate sizes.

Sprocket size is the easiest way to relate gear size on a chain-drive bicycle. It's the number of teeth of the two sprockets, the front chainring and rear cog. Thus, a bike with a 42-tooth chainring and a 17-tooth cog has what is said to be a "42 17." This is often written down as 42 x 17, even though it should be 42 : 17 as the gear ratio is 42 divided by 17.

Gear ratio is the basis for other gear measures. It's the relative measure of crank to wheel rotation, as each turn of the crank results in so many turns of the wheel. On a chain-drive bike, it's the number of teeth on the front chainring divided by the number of teeth on the rear cog. Therefore, a 42-tooth chainring and 17-tooth cog (42/17) has a 2.47 gear ratio.

Gear inches is the formula commonly used by English speakers. It's a nominal measure of gear ratio times drive wheel diameter in inches, and derives from high-wheelers who referred to wheel size by diameter in inches, saying "I ride a 56-inch wheel." A standard 27-inch wheel bike with a 42/17 sprocket combination (2.47 gear ratio) has 66.7 gear inches.

Development is the term for Metric system users to define the distance traveled in one pedal rotation, measured as gear ratio times wheel circumference in meters. A bike with a 42/17 sprocket (2.47 gear ratio) and 700c wheels (2135mm circumference) has 5.27 meters development.

Rollout is the best way to measure wheel circumference. In bike racing, it's the official way to regulate development. Instead of measuring wheel circumference by multiplying pi (3.14) to wheel diameter, it's more accurate to do a rollout of the distance of one wheel rotation, with a cyclist mounted on the bike with properly inflated tires. To measure meters development, rollout is the distance the drive wheel travels in one crank rotation.

Gain Ratio is a new measure, a pure ratio that calculates wheel radius divided by crank length times the gear ratio. A road bike with 700c wheels (340mm radius), 170mm length cranks, and a 42/17 sprocket combination (2.47 gear ratio) has a gain ratio of 4.94.

Many wonder which gear measure is best. While it's easier to convert millimeters to kilometers than inches to miles, the best measure is the one that works for you and your milieu.

Gear Inches Chart for 700C and 27-inch Wheels

This chart applies to a standard 27-inch road or track wheel. It's a basic guide for a 27 x 1-1/4-inch rim with a 28-630 clincher tire, or a 700c rim with a 23-622 clincher tire, or a 27-inch tubular tire and rim, formerly known as a 28-inch. Among these nominal tire sizes, actual diameters range from 26.75 to 27.25 inches (or 670 to 695 millimeters), depending on tire tread size.

Select front chainrings from orange columns
Select rear cogs from green rows


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